3GPP (3rd Generation Partnership Project) is a project to study and create specifications of a mobile communication system based on a network evolved from W-CDMA (Wideband-Code Division Multiple Access) and GSM (Global System for Mobile Communications). In 3GPP, W-CDMA has been standardized as the third generation cellular mobile communication system and is being put into service in sequence. In addition, HSDPA (High-speed Downlink Packet Access) with a still higher communication speed has been also standardized and put into service. In 3GPP, consideration is underway with regard to evolution of the third generation radio access technology (referred to as “LTE (Long Term Evolution)” or “EUTRA (Evolved Universal Terrestrial Radio Access)”, in the following), and a mobile communication system which realizes data transmission and reception with a higher speed using a wider frequency band (referred to as “LTE-A (Long Term Evolution-Advanced)” or “Advanced-EUTRA”, in the following).
OFDMA (Orthogonal Frequency Division Multiple Access) method which realizes user multiplexing using mutually orthogonal subcarriers, and SC-FDMA (Single Carrier-Frequency Division Multiple Access) method are under consideration as the communication method in LTE. In other words, OFDMA method which is a multi-carrier communication method is proposed for a downlink, and SC-FDMA method which is a single-carrier communication method is proposed for an uplink.
As the communication method in LTE-A, on the other hand, it is being considered to introduce OFDMA method for the downlink, and Clustered-SC-FDMA (referred to as Clustered-Single Carrier-Frequency Division Multiple Access, DFT-s-OFDM with Spectrum Division Control, or DFT-precoded OFDM) method in addition to SC-FDMA method, for the uplink. Here, in LTE and LTE-A, SC-FDMA method and Clustered-SC-FDMA method, which are proposed as the uplink communication method, are characteristic in that the PAPR (Peak to Average Power Ratio) when transmitting data (information) can be suppressed to a low level.
In addition, although the frequency band used in a general mobile communication method is contiguous, it is being considered in LTE-A to use a plurality of contiguous and/or discontiguous frequency bands (referred to as “Carrier Component (CC)”, or “Component Carrier (CC)”, in the following) in a multiple manner to operate them as one frequency band (as referred to as Spectrum aggregation, Carrier aggregation, Frequency aggregation, etc.). Furthermore, it is also proposed to use different frequency band widths for the downlink communication and the uplink communication (Asymmetric carrier aggregation) in order to allow the base station apparatus and the mobile station apparatus to communicate using a wide frequency band in a more flexible manner (see non-patent document 1).
FIG. 10 is an explanatory view illustrating a mobile communication system with the carrier aggregation of the conventional technology. Using the same bandwidth for a frequency band used for the downlink (DL) communication and for a frequency band used for the uplink (UL) communication as shown in FIG. 10 (also referred to as Symmetric carrier aggregation). As shown in FIG. 10, the base station apparatus and the mobile station apparatus can communicate with each other in a wide frequency band including a plurality of carrier components by using a plurality of carrier components which is contiguous and/or discontiguous frequency bands in a multiple manner. FIG. 10 shows that the frequency band used for the downlink communication having a bandwidth of 100 MHz (also referred to as DL system band, or DL system bandwidth, in the following), for example, includes five downlink carrier components (DCC1: Downlink Component Carrier 1, DCC2, DCC3, DCC4 and DCC5) each having a bandwidth of 20 MHz. Additionally, as an example, it is shown that the frequency band used for the uplink communication (also referred to as UL system band, or UL system bandwidth, in the following) having a bandwidth of 100 MHz includes five Uplink Carrier Components (UCC1: Uplink Component Carrier 1, UCC2, UCC3, UCC4 and UCC5) each having a bandwidth of 20 MHz.
In FIG. 10, downlink channels such as a Physical Downlink Control Channel (PDCCH, in the following), a Physical Downlink Shared Channel (PDSCH, in the following) or the like are mapped on each downlink carrier component. The base station apparatus transmits using the PDCCH, to the mobile station apparatus, control information (resource allocation information, MCS (Modulation and Coding Scheme) information, HARQ (Hybrid Automatic Repeat Request) processing information, or the like) for transmitting a downlink transport block to be transmitted using the PDSCH, and transmits the downlink transport block to the mobile station apparatus using the PDSCH. In other words, in FIG. 10, the base station apparatus can transmit up to five downlink transport blocks to the mobile station apparatus in the same subframe.
In addition, uplink channels such as a Physical Uplink Control Channel (PUCCH, in the following), a Physical Uplink Shared Channel (PUSCH, in the following), or the like are mapped on each uplink carrier component. The mobile station apparatus transmits using the PUCCH and/or the PUSCH, to the base station apparatus, Uplink Control Information (UCI, also referred to as UCS: Uplink Control Signaling) such as control information of the HARQ for the PDCCH and/or the downlink transport block, channel state information, or a scheduling request. Here, the control information of the HARQ is information indicating ACK/NACK (Positive Acknowledgement/Negative Acknowledgement, ACK signal or NACK signal) and/or information indicating DTX (Discontinuous Transmission) for the PDCCHs and/or the downlink transport blocks. The information indicating the DTX is information indicating that the mobile station apparatus failed to detect the PDCCH from the base station apparatus. Here, in FIG. 8, there may exist a downlink/uplink carrier component on which any of the downlink/uplink channels such as the PDCCH, the PDSCH, the PUCCH, the PUSCH, or the like is not mapped.
Similarly, FIG. 11 is an explanatory view illustrating a mobile communication system with the Asymmetric carrier aggregation of the conventional technology. As shown in FIG. 11, the base station apparatus and the mobile station apparatus can communicate with each other in a wide frequency band using different bandwidths for a frequency band used for the downlink communication and for a frequency band used for the uplink communication and using carrier components which are contiguous and/or discontiguous frequency bands constituting the frequency bands in a multiple manner. FIG. 11 shows that the frequency band used for the downlink communication having a bandwidth of 100 MHz, for example, includes five downlink carrier components (DCC1, DCC2, DCC3, DCC4 and DCC5) each having a bandwidth of 20 MHz, and that the frequency band used for the uplink communication having a bandwidth of 40 MHz includes two uplink carrier components (UCC1 and UCC2) each having a bandwidth of 20 MHz. In FIG. 11, the downlink/uplink channels are mapped on each downlink/uplink carrier component, and the base station apparatus can transmit a plurality of downlink transport blocks to the mobile station apparatus in the same subframe using a plurality of PDSCHs allocated using a plurality of PDCCHs. In addition, the mobile station apparatus can transmit using the PUCCH and/or the PUSCH, to the base station apparatus, the Uplink Control Information (UCI) such as the control information of the HARQ for the PDCCHs and/or the downlink transport blocks, the channel state information, or the scheduling request.